| Message ID | 20210914191045.2234020-6-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | x86: Add support for Clang CFI | expand |
On Tue, Sep 14, 2021 at 12:11 PM Sami Tolvanen <samitolvanen@google.com> wrote: > > If allocate_probes fails, func_remove replaces the old function > with a pointer to tp_stub_func, which is called using a mismatching > function pointer that's will always trip indirect call checks with > CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define > tp_stub_func to allow it to pass CFI checking. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > kernel/tracepoint.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index 64ea283f2f86..58acc7d86c3f 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -99,10 +99,7 @@ struct tp_probes { > }; > > /* Called in removal of a func but failed to allocate a new tp_funcs */ > -static void tp_stub_func(void) > -{ > - return; > -} > +static DEFINE_CFI_IMMEDIATE_RETURN_STUB(tp_stub_func); > > static inline void *allocate_probes(int count) > { > -- > 2.33.0.309.g3052b89438-goog >
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 64ea283f2f86..58acc7d86c3f 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -99,10 +99,7 @@ struct tp_probes { }; /* Called in removal of a func but failed to allocate a new tp_funcs */ -static void tp_stub_func(void) -{ - return; -} +static DEFINE_CFI_IMMEDIATE_RETURN_STUB(tp_stub_func); static inline void *allocate_probes(int count) {
If allocate_probes fails, func_remove replaces the old function with a pointer to tp_stub_func, which is called using a mismatching function pointer that's will always trip indirect call checks with CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define tp_stub_func to allow it to pass CFI checking. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- kernel/tracepoint.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)